AirPods Pro 3 corroded charging contacts

My 5 week old AirPods Pro 3 have started having charging issues when seated in the charging case. I took them to the local(ish) Genius Bar, and was told the problem was corrosion caused by oxidation with contact from moisture.

Apparently this is not covered by warranty and it's £80 to replace the case. While I understand the diagnosis and the cause, I disagree with the warranty statement, if something won't last 5 weeks with pods being seated on the contacts after use, then the material selected for the charging contacts is not fit for purpose and apple and I disagree over this.

As I don't want to pay another £80 for a replacement case equally susceptible to corrosion, can the existing corrosion be removed from the contacts without damaging the case?

Thanks